In wireless communications wireless channels are provided between two or more nodes such as fixed and/or mobile communication devices, access points such as base stations, servers, machine type devices, and so on. Examples of wireless systems include public land mobile networks (PLMN) such as cellular networks, satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN) and/or Worldwide Interoperability for Microwave Access (WiMax). A device for such systems is provided with appropriate signal receiving and transmitting apparatus for enabling communications with other parties. Wireless systems enable mobility for users where a mobile device can communicate over an air interface with another communication device such as e.g. a base station and/or other user equipment.
Data transmissions between parties may need to be secured. Applications, for example banking, shopping, email and so on, may rely on secure transactions over the Internet or other networks open to attacks. Increase in Internet commerce and transfer of computing tasks to remote servers (e.g. “cloud computing”) has emphasized the need to maintain appropriate security of communications. Security can be provided based on a cryptographic protocol. Current cryptographic schemes (e.g. public key encryption) rely on the hardness of solving certain mathematical problems. For example, the commonly used RSA encryption algorithm is based on the hardness of factoring a large number into its prime factors. This is a hard problem using standard computer technology but can become solvable with development of more powerful computing technologies, for example by a future quantum computer. In the context of mobile communications an issue may arise in that the mobile devices are often handheld or otherwise portable and thus should be as lightweight and simple as possible. Because of the mobility of the devices their location relative to the other party might not be known. It is noted that the above discussed issues are not limited to any particular communication environments and apparatus but may occur in any context where security is needed for wireless communications.
Embodiments of the invention aim to address one or several of the above issues.